U.S. patent number 9,619,044 [Application Number 14/048,430] was granted by the patent office on 2017-04-11 for capacitive and resistive-pressure touch-sensitive touchpad.
This patent grant is currently assigned to Google Inc.. The grantee listed for this patent is GOOGLE INC.. Invention is credited to Matthew Dominic Tenuta.
United States Patent |
9,619,044 |
Tenuta |
April 11, 2017 |
Capacitive and resistive-pressure touch-sensitive touchpad
Abstract
A trackpad device includes a top surface, a capacitive sensor
operably coupled to the top surface, a resistive sensor disposed
below the capacitive sensor and at least one controller operably
coupled to the capacitive sensor and to the resistive sensor. The
at least one controller and the capacitive sensor are configured to
detect one or more objects on the top surface. The at least one
controller and the resistive sensor are configured to detect the
one or more objects on the top surface independent of the detection
by the at least one controller and the capacitive sensor. The at
least one controller is configured to determine locations of the
one or more objects on the top surface using information from the
detection by the at least one controller and capacitive sensor and
information from the detection by the at least one controller and
the resistive sensor.
Inventors: |
Tenuta; Matthew Dominic (San
Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
GOOGLE INC. |
Mountain View |
CA |
US |
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Assignee: |
Google Inc. (Mountain View,
CA)
|
Family
ID: |
52690509 |
Appl.
No.: |
14/048,430 |
Filed: |
October 8, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150084868 A1 |
Mar 26, 2015 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61882333 |
Sep 25, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
3/0213 (20130101); G06F 3/044 (20130101); G06F
3/03547 (20130101); G06F 3/04184 (20190501); G06F
3/045 (20130101); G06F 3/038 (20130101); G06F
2203/04106 (20130101); G06F 2203/04105 (20130101) |
Current International
Class: |
G06F
3/044 (20060101); G06F 3/045 (20060101); G06F
3/038 (20130101); G06F 3/041 (20060101); G06F
3/0354 (20130101); G06F 3/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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102012201379 |
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Aug 2013 |
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DE |
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2011/156447 |
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Dec 2011 |
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WO |
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Other References
International Search Report and Written Opinion for PCT Patent
Application No. PCT/US2014/054722, mailed on Dec. 10, 2014, 13
pages. cited by applicant.
|
Primary Examiner: Dicke; Chad
Attorney, Agent or Firm: Brake Hughes Bellermann LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 61/882,333, filed Sep. 25, 2013, entitled "Pressure-Sensitive
Trackpad," which is hereby incorporated by reference in its
entirety.
Claims
What is claimed is:
1. A trackpad device, comprising: a top surface; a capacitive
sensor operably coupled to the top surface and that is configured
to obtain touch data; a resistive sensor disposed below the
capacitive sensor and that is configured to obtain pressure data,
wherein the resistive sensor includes: a top resistive layer, a
bottom resistive layer, and a spacer matrix disposed between the
top resistive layer and the bottom resistive layer; and at least
one controller operably coupled to the capacitive sensor and to the
resistive sensor, wherein: the at least one controller and both the
capacitive sensor and the resistive sensor are configured to detect
one or more objects on the top surface using independent and
substantially simultaneous detection scans, wherein the detection
by the resistive sensor is independent of the detection by the
capacitive sensor and the resistive sensor obtains the pressure
data, which includes location-specific change information, by
measuring a force applied by the one or more objects using the top
resistive layer, the bottom resistive layer and the spacer matrix,
and the at least one controller is configured to correlate the
touch data and the pressure data to determine locations of the one
or more objects on the top surface, wherein uncorrelated touch data
and pressure data is rejected by the at least one controller,
correlated touch data and pressure data that is further filtered by
resolving geometric patterns in the pressure data and comparing the
resolved geometric patterns with pattern filtering criteria is
rejected by the at least one controller, correlated touch data and
pressure data that is not rejected by the resolved geometric
pattern filtering is used by the at least one controller to detect
movement of the one or more objects by comparing current pressure
data with previous pressure data and by comparing current touch
data with previous touch data, correlated touch data and pressure
data that is not rejected by the resolved geometric pattern
filtering, where the current pressure data exceeds a first pressure
threshold, is used to cause selection of an item in a user
interface, and correlated touch data and pressure data that is not
rejected by the resolved geometric pattern filtering, where the
current pressure data exceeds a second pressure threshold, is used
to cause opening of the item in the user interface.
2. The trackpad device of claim 1, wherein the at least one
controller includes: a first controller that is operably coupled to
the capacitive sensor; and a second controller that is operably
coupled to the resistive sensor, wherein the first controller is
different from the second controller.
3. The trackpad device of claim 2, further comprising a
synchronizer that is operably coupled to the first controller and
the second controller, the synchronizer being configured to
synchronize detection scans from the first controller and the
capacitive sensor with detection scans from the second controller
and the resistive sensor.
4. The trackpad device of claim 3, wherein the synchronizer is
configured to run the detection scans from the first controller and
the capacitive sensor simultaneously with the detection scans from
the second controller and the resistive sensor.
5. The trackpad device of claim 1, wherein: the top surface is
divided into a plurality of regions; and the at least one
controller is configured to determine the locations of the one or
more objects on the top surface by using the detections with the
capacitive sensor in one or more of the regions to filter the
detections with the resistive sensor in the same regions.
6. The trackpad device of claim 1, wherein the capacitive sensor is
a single layer capacitive sensor.
7. The trackpad device of claim 1, wherein the capacitive sensor is
a multi-layer capacitive sensor.
8. The trackpad device of claim 1, wherein: the trackpad device
includes both a trackpad area and a keyboard area; and the at least
one controller is configured to use the capacitive sensor and the
resistive sensor to distinguish between keystrokes on the keyboard
area and movement on the trackpad area.
9. The trackpad device of claim 8, wherein at least a portion of
the trackpad area and the keyboard area overlap.
10. A computing device, comprising: a display device, the computing
device being configured to render a graphical user interface (GUI)
on the display device; a trackpad apparatus configured to
facilitate user interaction with the GUI, the trackpad apparatus
comprising: a top surface; a capacitive sensor operably coupled to
the top surface and that is configured to obtain touch data; a
resistive sensor disposed below the capacitive sensor and that is
configured to obtain pressure data, wherein the resistive sensor
includes: a top resistive layer, a bottom resistive layer, and a
spacer matrix disposed between the top resistive layer and the
bottom resistive layer; and at least one controller operably
coupled to the capacitive sensor and to the resistive sensor,
wherein: the at least one controller and both the capacitive sensor
and the resistive sensor are configured to detect one or more
objects on the top surface using independent and substantially
simultaneous detection scans, wherein the detection by the
resistive sensor is independent of the detection by the capacitive
sensor and the resistive sensor obtains the pressure data, which
includes location-specific change information, by measuring a force
applied by the one or more objects using the top resistive layer,
the bottom resistive layer and the spacer matrix, and the at least
one controller is configured to correlate the touch data and the
pressure data to determine locations of the one or more objects on
the top surface, wherein uncorrelated touch data and pressure data
is rejected by the at least one controller, correlated touch data
and pressure data that is further filtered by resolving geometric
patterns in the pressure data and comparing the resolved geometric
patterns with the pattern filtering criteria is rejected by the at
least one controller, correlated touch data and pressure data that
is not rejected by the resolved geometric pattern filtering is used
by the at least one controller to detect movement of the one or
more objects by comparing current pressure data with previous
pressure data and by comparing current touch data with previous
touch data, correlated touch data and pressure data that is not
rejected by the resolved geometric pattern filtering, where the
current pressure data exceeds a first pressure threshold, is used
to cause selection of an item in a user interface, and correlated
touch data and pressure data that is not rejected by the resolved
geometric pattern filtering, where the current pressure data
exceeds a second pressure threshold, is used to cause opening of
the item in the user interface.
11. The computing device of claim 10, wherein: the at least one
controller and the resistive sensor are collectively further
configured to, for one or more corresponding locations on the top
surface of the trackpad apparatus, detect a respective amount of
pressure applied to the top surface of the trackpad apparatus; and
user interaction with the GUI is further based on the detected
respective amounts of pressure for the one or more corresponding
locations on the top surface of the trackpad apparatus.
12. The computing device of claim 10, wherein the at least one
controller includes: a first controller that is operably coupled to
the capacitive sensor; and a second controller that is operably
coupled to the resistive sensor, wherein the first controller is
different from the second controller.
13. The computing device of claim 12, further comprising a
synchronizer that is operably coupled to the first controller and
the second controller, the synchronizer being configured to
synchronize detection scans from the first controller and the
capacitive sensor with detection scans from the second controller
and the resistive sensor.
14. The computing device of claim 13, wherein the synchronizer is
configured to run the detections scans from the first controller
and the capacitive sensor simultaneously with the detection scans
from the second controller and the resistive sensor.
15. The computing device of claim 10, wherein: the trackpad
apparatus includes both a trackpad area and a keyboard area; and
the at least one controller is configured to use the capacitive
sensor and the resistive sensor to distinguish between keystrokes
on the keyboard area and movement on the trackpad area.
16. The computing device of claim 15, wherein at least a portion of
the trackpad area and the keyboard area overlap.
17. A method, comprising: detecting one or more objects on a top
surface of a trackpad device using at least one controller and both
a capacitive sensor that is configured to obtain touch data and a
resistive sensor that is configured to obtain pressure data
independent of the capacitive sensor using independent and
substantially simultaneous detection scans, wherein the resistive
sensor obtains the pressure data, which includes location-specific
change information, by measuring a force applied by the one or more
objects using the resistive sensor including a top resistive layer,
a bottom resistive layer and a spacer matrix disposed between the
top resistive layer and the bottom resistive layer; and determining
locations of the one or more objects on the top surface by
correlating the touch data and the pressure data, wherein
uncorrelated touch data and pressure data is rejected by the at
least one controller, correlated touch data and pressure data that
is further filtered by resolving geometric patterns in the pressure
data and comparing the resolved geometric patterns with the pattern
filtering criteria is rejected by the at least one controller,
correlated touch data and pressure data that is not rejected by the
resolved geometric pattern filtering is used by the at least one
controller to detect movement of the one or more objects by
comparing current pressure data with previous pressure data and by
comparing current touch data with previous pressure data,
correlated touch data and pressure data that is not rejected by the
resolved geometric pattern filtering, where the current pressure
data exceeds a first pressure threshold, is used to cause selection
of an item in a user interface, and correlated touch data and
pressure data that is not rejected by the resolved geometric
pattern filtering, where the current pressure data exceeds a second
pressure threshold, is used to cause opening of the item in the
user interface.
18. The method of claim 17, wherein the trackpad device includes
both a trackpad area and a keyboard area, the method further
comprising distinguishing between keystrokes on the keyboard area
and movement on the trackpad area using the capacitive sensor and
the resistive sensor.
Description
TECHNICAL FIELD
This document relates, generally, to trackpad (touchpad) pointing
devices.
BACKGROUND
Trackpads, which may also be referred to as touchpads, are often
used with computing devices, e.g., as pointing devices to
facilitate user interaction with an associated computing device.
Trackpads may be used with a computing device in place of, or in
addition to, a mouse pointing device. For instance, trackpads are
often implemented as integrated pointing devices for laptop
computing devices, notebook computing devices and netbook computing
devices. A trackpad may also be implemented as a non-integrated
device that is coupled (e.g., as a peripheral device) to a
computing device, such as a desktop computing device or a server
computing device, as some examples. Trackpads may, of course, be
implemented in other devices as well.
Trackpad (touchpad) devices include a tactile sensing surface
(e.g., a capacitive sensing surface), where the trackpad device is
generally configured to facilitate interaction by a user with a
graphical user interface (GUI) for an associated computing device.
For instance, a trackpad device may be configured to detect
position and motion of a user's finger or fingers that are in
contact with the tactile sensing surface. The detected motion
and/or position of a user's finger or fingers on the trackpad may
then be used, by the computing device, to determine a relative
position on a display screen (in a GUI) that corresponds with the
position of the user's finger (or fingers), or to affect movement
of a cursor in the GUI, as some examples.
Current trackpads, however, have certain drawbacks. For instance,
in some implementations, a user tapping a trackpad's surface may be
used to indicate a mouse click, such as to select an item, locate a
cursor or launch a program, as some examples. However, in such
approaches, a user inadvertently and briefly touching the trackpad
may be recognized as unwanted mouse click, which can result in
undesired effects and be frustrating for the user. In other
instances, a trackpad device may include separate buttons. In such
implementations, a user may have to position his or her finger on
the trackpad surface and simultaneously click one of the separate
buttons in order to perform certain interactions with a GUI (such
as to launch an application associated with an icon, select an
object in the GUI or move an object in the GUI, as some examples),
which may be awkward for the user.
SUMMARY
In a general aspect, a trackpad device includes a top surface, a
capacitive sensor operably coupled to the top surface, a resistive
sensor disposed below the capacitive sensor and at least one
controller operably coupled to the capacitive sensor and to the
resistive sensor. The at least one controller and the capacitive
sensor are configured to detect one or more objects on the top
surface. The at least one controller and the resistive sensor are
configured to detect the one or more objects on the top surface
independent of the detection by the at least one controller and the
capacitive sensor. The at least one controller is configured to
determine locations of the one or more objects on the top surface
using information from the detection by the at least one controller
and capacitive sensor and information from the detection by the at
least one controller and the resistive sensor.
Implementations may include one or more of the following features.
For example, the resistive sensor may include a top resistive
layer, a bottom resistive layer and a spacer matrix disposed
between the top resistive layer and the bottom resistive layer,
where the at least one controller and the resistive sensor are
configured to detect the one or more objects on the top surface by
measuring a force applied by the one or more objects using the top
resistive layer, the bottom resistive layer and the spacer
matrix.
The at least one controller may include a first controller that is
operably coupled to the capacitive sensor and a second controller
that is operably coupled to the resistive sensor, where the first
controller is different from the second controller. The trackpad
device may further include a synchronizer that is operably coupled
to the first controller and the second controller. The synchronizer
may be configured to synchronize detection scans from the first
controller and the capacitive sensor with detection scans from the
second controller and the resistive sensor. The synchronizer may be
configured to run the detection scans from the first controller and
the capacitive sensor simultaneously with the detection scans from
the second controller and the resistive sensor.
The top surface may be divided into a plurality of regions and the
at least one controller may be configured to determine the
locations of the one or more objects on the top surface by using
the detections with the capacitive sensor in one or more of the
regions to filter the detections with the resistive sensor in the
same regions. The capacitive sensor may be a single layer
capacitive sensor. The capacitive sensor may be a multi-layer
capacitive sensor. The trackpad device may include both a trackpad
area and a keyboard area and the at least one controller may be
configured to use the capacitive sensor and the resistive sensor to
distinguish between keystrokes on the keyboard area and movement on
the trackpad area. At least a portion of the trackpad area and the
keyboard area may overlap.
In another general aspect, a computing device includes a display
device, where the computing device is configured to render a
graphical user interface (GUI) on the display device. The computing
device includes a trackpad apparatus configured to facilitate user
interaction with the GUI. The trackpad apparatus includes a top
surface, a capacitive sensor operably coupled to the top surface, a
resistive sensor disposed below the capacitive sensor and at least
one controller operably coupled to the capacitive sensor and to the
resistive sensor. The at least one controller and the capacitive
sensor are configured to detect one or more objects on the top
surface. The at least one controller and the resistive sensor are
configured to detect the one or more objects on the top surface
independent of the detection by the at least one controller and the
capacitive sensor. The at least one controller is configured to
determine locations of the one or more objects on the top surface
using information from the detection by the at least one controller
and capacitive sensor and information from the detection by the at
least one controller and the resistive sensor.
Implementations may include one or more of the following features.
For example, the at least one controller and the resistive sensor
may be collectively further configured to, for one or more
corresponding locations on the top surface of the trackpad
apparatus, detect a respective amount of pressure applied to the
top surface of the trackpad apparatus and user interaction with the
GUI may be further based on the detected respective amounts of
pressure for the one or more corresponding locations on the top
surface of the trackpad apparatus. The resistive sensor may include
a top resistive layer, a bottom resistive layer and a spacer matrix
disposed between the top resistive layer and the bottom resistive
layer, where the at least one controller and the resistive sensor
are configured to detect the one or more objects on the top surface
by measuring a force applied by the one or more objects using the
top resistive layer, the bottom resistive layer and the spacer
matrix.
The at least one controller may include a first controller that is
operably coupled to the capacitive sensor and a second controller
that is operably coupled to the resistive sensor, where the first
controller is different from the second controller. The computing
device may further include a synchronizer that is operably coupled
to the first controller and the second controller, where the
synchronizer may be configured to synchronize detection scans from
the first controller and the capacitive sensor with detection scans
from the second controller and the resistive sensor. The
synchronizer may be configured to run the detections scans from the
first controller and the capacitive sensor simultaneously with the
detection scans from the second controller and the resistive
sensor.
The trackpad apparatus may include both a trackpad area and a
keyboard area and the at least one controller may be configured to
use the capacitive sensor and the resistive sensor to distinguish
between keystrokes on the keyboard area and movement on the
trackpad area. At least a portion of the trackpad area and the
keyboard area may overlap.
In another general aspect, a method includes detecting one or more
objects on a top surface of a trackpad device using at least one
controller and a capacitive sensor, detecting one or more objects
on the top surface using the at least one controller and a
resistive sensor independent of the detection by the at least one
controller and the capacitive sensor and determining locations of
the one or more objects on the top surface using information from
the detection by the at least one controller and capacitive sensor
and information from the detection by the at least one controller
and the resistive sensor.
Implementations may include one or more of the following features.
For example, the trackpad device may include both a trackpad area
and a keyboard area and the method further includes distinguishing
between keystrokes on the keyboard area and movement on the
trackpad area using the capacitive sensor and the resistive
sensor.
In another general aspect, an apparatus includes means for
detecting one or more objects on a top surface of a trackpad device
using at least one controller and a capacitive sensor, means for
detecting one or more objects on the top surface using the at least
one controller and a resistive sensor independent of the detection
by the at least one controller and the capacitive sensor and means
for determining locations of the one or more objects on the top
surface using information from the detection by the at least one
controller and capacitive sensor and information from the detection
by the at least one controller and the resistive sensor.
Implementations may include one or more of the following features.
For example, the trackpad device may include both a trackpad area
and a keyboard area and the method further includes means for
distinguishing between keystrokes on the keyboard area and movement
on the trackpad area using the capacitive sensor and the resistive
sensor.
The details of one or more implementations are set forth in the
accompanying drawings and the description below. Other features
will be apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a drawing illustrating a computing device in accordance
with an example implementation.
FIG. 1B is a drawing illustrating a computing device in accordance
with an example implementation.
FIG. 2A is a block diagram illustrating a pressure-sensitive
trackpad apparatus in accordance with an example
implementation.
FIG. 2B is a block diagram illustrating a pressure-sensitive
trackpad apparatus in accordance with an example
implementation.
FIG. 3 is a diagram illustrating a pressure-sensitive trackpad
apparatus in accordance with an example implementation.
FIGS. 4A and 4B are diagrams illustrating operation of a
pressure-sensitive trackpad apparatus in accordance with an example
implementation.
FIG. 5 is a diagram illustrating pattern matching and rejection
criteria in accordance with an example implementation.
FIG. 6 is an example flow diagram illustrating example operations
of the trackpad apparatus of FIGS. 2A, 2B, 3, 4A and 4B as
implemented in example computing devices of FIGS. 1A and 1B.
DETAILED DESCRIPTION
FIG. 1A is a drawing illustrating a computing device 100 in
accordance with an example implementation. It will be appreciated
that the computing device 100 is shown by way of example, and for
purposes of illustration. In some implementations, the computing
device 100 may take the form of a laptop computer, a notebook
computer or netbook computer. In other implementations, the
computing device 100 may have other configurations. For instance,
the computing device 100 may be a tablet computer, a desktop
computer, a server computer, or a number of other computing or
electronics devices where a pressure-sensitive trackpad apparatus
(trackpad device) 130, such as those described herein, may be used
to facilitate interaction with a corresponding device (e.g., via a
graphical user interface (GUI)). Throughout this document, the
terms trackpad, trackpad device, trackpad apparatus, touchpad,
touchpad device and touchpad apparatus may be used interchangeably.
Also throughout this document, the terms computing device,
computing system and electronic device may be used
interchangeably.
The computing device 100 shown in FIG. 1A includes a display device
110, a keyboard 120, a pressure-sensitive trackpad apparatus 130
and a chassis 140. As indicated in FIG. 1A, the display device 110
(e.g., in conjunction with other elements of the computing device
100) may be configured to render a GUI that allows a user to
interact with the computing device 100, such as to run programs,
browse the Internet or World Wide Web, or draft documents, as some
examples. A user of the computing device 100 may interact with the
computing device 100 via the GUI rendered on the display device 110
using the keyboard 120, such as to enter text or commands. The
keyboard 120 may take a number of forms, and the particular
arrangement of the keyboard 120 will depend on the particular
implementation.
A user may also interact with the computing device 100 via the GUI
rendered on the display device 110 using the pressure-sensitive
trackpad 130, such as to move a cursor, select objects, launch
programs from icons or move objects in the GUI, as some examples.
Of course, other interactions with the GUI are possible using the
pressure-sensitive trackpad 130. The trackpad 130 may be
implemented in a number of ways, such as using the techniques
described herein, for example. It will be appreciated that the
particular configuration of the trackpad 130 may vary and the
configuration used will depend on the specific implementation. For
instance, the trackpad may be larger, or smaller in some
implementations. For example, in one implementation, the trackpad
may be increased in size and be disposed in (replace) the area that
includes the keyboard 120, such as described below with respect to
FIG. 1B.
The chassis 140 of the computing device 100 may be used to house
various components of the computing device 110, such as the
trackpad 130, a processor motherboard and system memory (e.g.,
including volatile and non-volatile memory), as well as a number of
other components. The chassis 140 may also be used to establish an
electrical ground, which may also be referred to as chassis ground,
for one or more components of the computing device 100, such as for
the trackpad 130. For instance, in one example, the chassis 140 may
comprise a metal frame within a polymer housing. In this example,
the metal frame of the chassis 140 may be connected to an
electrical ground of a power supply that is included in the
computing device 100 in order to provide electrical (chassis)
ground to the trackpad 130. It will be appreciated that other
arrangements for providing a chassis ground are possible.
FIG. 1B is a drawing illustrating a computing device 150 in
accordance with an example implementation. It will be appreciated
that the computing device 150 is shown by way of example, and for
purposes of illustration. In some implementations, the computing
device 150 may take the form of a laptop computer, a notebook
computer or netbook computer. In other implementations, the
computing device 150 may have other configurations. For instance,
the computing device 150 may be a tablet computer, a desktop
computer, a server computer, or a number of other computing or
electronics devices where a combined keyboard and
pressure-sensitive trackpad apparatus (trackpad device) 170, such
as those described herein, may be used to facilitate interaction
with a corresponding device (e.g., via a graphical user interface
(GUI)).
The computing device 150 shown in FIG. 1B includes a display device
160, a combined keyboard and pressure-sensitive trackpad apparatus
170 and a chassis 180. As indicated in FIG. 1B, the display device
160 (e.g., in conjunction with other elements of the computing
device 150) may be configured to render a GUI that allows a user to
interact with the computing device 150, such as to run programs,
browse the Internet or World Wide Web, or draft documents, as some
examples. A user of the computing device 150 may interact with the
computing device 150 via the GUI rendered on the display device 160
using the combined keyboard and pressure-sensitive trackpad 170.
For instance, the user may use the keyboard and trackpad 170 both
to enter text or commands and for actions such as moving a cursor,
selecting objects, launching programs from icons or moving objects
in the GUI, as some examples. The keyboard and trackpad 170 may
take a number of forms, and the particular arrangement of the
keyboard and trackpad 170 will depend on the particular
implementation. The keyboard and trackpad 170 may be implemented in
a number of ways, such as using the techniques described herein,
for example.
It will be appreciated that the particular configuration of the
keyboard and trackpad 170 may vary and the configuration used will
depend on the specific implementation. For instance, keyboard and
trackpad 170 may be configured to function as both the keyboard and
the trackpad and the keyboard and trackpad 170 may be configured to
distinguish between keyboard actions and trackpad actions.
The chassis 180 of the computing device 150 may be used to house
various components of the computing device 150, such as the
keyboard and trackpad 170, a processor motherboard and system
memory (e.g., including volatile and non-volatile memory), as well
as a number of other components. The chassis 180 may also be used
to establish an electrical ground, which may also be referred to as
chassis ground, for one or more components of the computing device
150, such as for the keyboard and trackpad 170. For instance, in
one example, the chassis 180 may comprise a metal frame within a
polymer housing. In this example, the metal frame of the chassis
180 may be connected to an electrical ground of a power supply that
is included in the computing device 150 in order to provide
electrical (chassis) ground to the keyboard and trackpad 170. It
will be appreciated that other arrangements for providing a chassis
ground are possible.
FIG. 2A is a block diagram illustrating a pressure-sensitive
trackpad apparatus 200 in accordance with an example
implementation. The trackpad 200 may be implemented, for example,
in the computing device 100 as the trackpad apparatus 130 and in
the computing device 150 as the keyboard and trackpad apparatus
170. Of course, the trackpad 200 may be implemented in conjunction
with other computing devices and the computing devices 100 and 150
may include pressure-sensitive trackpads having other
configurations. For example, FIG. 2A illustrates a single
controller 230. In other example implementations, more than one
controller may be used, for instance as discussed below in more
detail below with respect to FIG. 2B.
As shown in FIG. 2A, the trackpad apparatus 200 includes a
capacitive sensor 210 (also referred to as a capacitive
touch-sensing pattern), a resistive sensor 220 (also referred to as
a resistive touch-sensing pattern), a controller 230 and pattern
matching/rejection criteria 240. It will be appreciated that the
configuration of the trackpad 200 is given by way of example and
for purposes of illustration. In certain implementations, the
trackpad 200 may include other elements, or may be arranged in
different fashions. For instance, the trackpad 200 may include an
insulating layer that is disposed between the capacitive sensor 210
and the resistive sensor 220. In other instances, the pattern
matching/rejection criteria 240 may be included in the controller
230. In still other implementations, pattern matching and/or
pattern rejection, such as described herein, may be performed by
other elements of a computing system (e.g., other than the
controller 230) in which the trackpad 200 is implemented.
In the trackpad 200, the capacitive sensor 210 may be disposed on a
top surface of the trackpad 200 and provide a tactile sensing
surface for detecting (e.g., in conjunction with the controller
230) the presence and/or movement of one or more electrically
conductive and electrically grounded objects, such as a user's
finger or fingers, for example. In an example implementation, the
capacitive sensor 210 may be implemented using a multi-layer array
(matrix) of capacitors. In such an approach, the capacitive sensor
210 may include a top layer of closely-spaced, parallel-arranged
conductors and a bottom layer of closely-spaced, parallel-arranged
conductors that are oriented in a perpendicular arrangement with
the conductors of the top layer. The top layer and the bottom layer
of the capacitive sensor 210 may be separated by an insulating
(dielectric) layer, such that the conductors in the top layer and
the bottom layer form respective capacitors, through the dielectric
layer, at each crossing point of a conductor in the top layer and a
conductor in the bottom layer. Such an arrangement may be used to
form a tightly spaced matrix of capacitors. In one example
implementation, the capacitive sensor 210 may be a single layer
sensor. In other example implementations, the capacitive sensor 210
may be a multi-layer capacitive sensor.
In such an approach, the controller 230 may be configured to
sequentially apply a high frequency signal (e.g., an alternating
current (AC) signal) between conductor pairs in such a
two-dimensional capacitor matrix. The amount of charge that is
coupled through the capacitors at each crossing point of the
conductors of the top layer and the conductors of the bottom layer
of capacitive sensor 210 would be proportional to the respective
capacitance at each crossing point. When the sensing surface of the
capacitive sensor 210 does not have any electrically conductive
objects in contact with it, charge coupling may be substantially
uniform across the capacitive matrix of the capacitive sensor
210.
However, when an electrically grounded object (e.g., an object that
is electrically grounded relative to the top layer of the
capacitive sensor 210), such as a user's finger or fingers, is
(are) placed in contact with the sensing surface of the capacitive
sensor 210, some of the charge from the capacitors in the contacted
area or areas would be shunted to the grounded object or objects.
The charge that is shunted to the grounded object or objects would
then result in a change (e.g., a decrease) in the apparent
capacitance in the area or areas with which the electrically
grounded objects or objects are in (electrical) contact with the
capacitive sensor 210.
The controller 230 may be configured to detect such changes in
apparent capacitance by detecting location-specific reductions in
charge coupling (e.g., at the contacted areas) in the capacitive
sensor 210. Accordingly, the controller 230, in conjunction with
the capacitive sensor 210, may detect the position or positions of
a user's finger or fingers on the capacitive sensor 210 and/or
movement of a user's finger or fingers across the capacitive sensor
210 based on detection and/or changes in location of such
location-specific reductions in charge coupling. Of course, other
approaches for implementing the capacitive sensor 210 are possible.
For purposes of this disclosure, such detected location-specific
reductions in charge coupling corresponding with the position(s) of
a user's finger or fingers and/or movement of a user's finger or
fingers on the capacitive sensor 210 may be referred to,
hereinafter, as "touch data" or "detection information" or
"information from the detection by the controller and the
capacitive sensor."
In the trackpad 200, the resistive sensor 220 may be disposed below
the capacitive sensor 210. The resistive sensor 220 may be
implemented using a multi-layer array of resistive elements that
includes a top layer of closely-spaced, parallel-arranged resistive
elements and a bottom layer of closely-spaced, parallel-arranged
resistive elements that are oriented in a perpendicular arrangement
with the resistive elements of the top layer. The top layer and the
bottom layer of the resistive sensor 220 may be separated by a
compressible membrane layer, such as a spacer matrix or dot
matrix.
In such an approach, the controller 230 may be configured to
sequentially apply a direct current (DC) signal (e.g., a DC
voltage) between resistive elements of the resistive sensor 220.
The controller in conjunction with the resistive sensor 220 is
configured to measure an amount of force applied by measuring a
voltage conducted through the resistive sensor layers. The amount
of voltage that is present through the resistive elements at each
crossing point of elements in the top layer and the elements in the
bottom layer would be proportional to the respective voltage at
each crossing point. When the resistive sensor 220 is not displaced
(e.g., at one or more locations) by an object or objects (e.g., a
user's finger or fingers) applying pressure to the surface of the
trackpad 200, voltage across the resistive sensor 220 may be
substantially uniform across its resistive matrix.
However, when pressure is applied at one or more locations on the
surface of the trackpad 200, this pressure may cause
location-specific displacement of the resistive sensor 220 at a
location or locations that is (are) coincident with the location or
locations where such pressure is applied. Such location-specific
displacement of the resistive sensor 220 may result in
corresponding location-specific changes in voltage in the resistive
sensor 220. Depending on the particular implementation, such
location-specification changes in voltage corresponding with the
location or locations at which pressure is applied may be detected
(e.g., by the controller 230) as location-specific increases in
voltage in the resistive sensor 220.
For instance, such location-specific changes in voltage in the
resistive sensor 220 may be detected as location-specific increases
in voltage (such as in the implementation shown in FIGS. 4A and
4B). The implementations illustrated in FIGS. 4A and 4B will be
described in further detail below. For purposes of this disclosure,
such detected location-specific changes in voltage resulting from
pressure applied to one or more locations on a trackpad surface may
be referred to, hereinafter, as "pressure data" or "force data" or
"detection information" or "information from the detection by the
controller and the resistive sensor."
In the trackpad apparatus 200 shown in FIG. 2A, the controller 230
may implemented in a number of manners. For instance, the
controller 230 may be implemented using a general purpose
programmable processor or controller. In other implementations, the
controller 230 may be implemented using an application specific
integrated circuit. In still other approaches, the controller 230
may be implemented using firmware and/or software in the form of
machine readable instructions that may be executed by a general
purpose processor or controller. The controller 230 may also be
implemented using a combination of the techniques discussed above,
or may be implemented using other techniques and/or devices.
The controller 230 may be configured to generate and coordinate
detection scans of the capacitive sensor 210 and the resistive
sensor 220 simultaneously or nearly simultaneously. Both sensors,
the capacitive sensor 210 and the resistive sensor 220, function
independent of one another. As discussed above, the controller 230
applies an AC signal to the capacitive sensor 210 and a DC signal
to the resistive sensor 220, so there is no risk of interference
between the signals. The signals from the capacitive sensor 210 can
be measured independently from the signals from the resistive
sensor 220. Similarly, the signals from the resistive sensor 220
can be measured independently from the signals from the capacitive
sensor 210.
In an example implementation, the controller 230 may use the
pattern matching/rejection criteria 240 (which is referred to,
hereinafter, as pattern filtering criteria 240) to filter touch
data and pressure data received from, respectively, the capacitive
sensor 210 and the resistive sensor 220. Examples of such criteria
are described below with respect to FIG. 5.
Briefly, however, the controller 230 may be configured to resolve
one or more geometric patterns corresponding with touch data
received from the capacitive sensor 210. For instance, if a user
places two fingers in contact with the capacitive sensor 210, the
controller 230 may resolve respective geometric patterns associated
with each of the user's fingers that are in contact with the
capacitive sensor 210 from touch data (e.g., location-specific
reductions in charge coupling) corresponding with each of the
user's fingers. The controller 230 may be further configured to
compare the resolved geometric patterns with the pattern filtering
criteria 240 and accept or reject the touch data (or portions of
the touch data) based on that comparison.
Such an approach may allow the trackpad apparatus 200 to reject
touch data that may be inadvertent or undesirable to use when
interacting with a GUI. For example, the pattern filtering criteria
240 may be used to reject touch data that results from a user
resting his or her palm, or the side of his or her hand on the
trackpad 200. Further, the pattern filtering criteria 240 may also
be used to accept touch data with certain patterns, such as
patterns that correspond with a user's fingertip or fingertips. The
controller 230 may also be configured to filter pressure-data in a
similar fashion, e.g., by resolving geometric patterns in the
pressure data and comparing those resolved patterns with the
pattern filtering criteria 240.
In other implementations, the controller 230 may be configured to
correlate touch data with pressure data and filter the pressure
data based on both the geometric patterns resolved from the touch
data and the pattern filtering criteria 240. In such an approach,
if the controller 230 identifies pressure data that does not have
corresponding touch data (e.g., a coincident location), that
pressure data may be filtered out and not provided to a
corresponding computing device to affect interaction with a GUI.
Also, in such an implementation, pressure data that does have
corresponding touch data may be further filtered by applying
geometric patterns resolved from the touch data (e.g., at
coincident location(s)) and the pattern filtering criteria 240 to
the pressure data. In one example implementation, a top surface of
the trackpad 200 may be divided into a plurality of regions. The
controller 230 may be configured to determine the locations of one
or more objects on the top surface by using detections by the
capacitive sensor 210 in one or more of the regions to filter the
detections with the resistive sensor 220 in the same regions.
The controller 230 may also be configured to detect movement of one
or more electrically conductive objects (e.g., a user's finger or
fingers) across the top surface of the trackpad apparatus based on
movement of the detected location-specific reductions in charge
coupling in the capacitive touch-sensing pattern. For instance, the
controller 230 may be configured to compare current touch data with
previous touch data in order to detect such movement. In like
fashion, the controller 230 may also be configured to detect one or
more objects applying pressure and moving across the top surface of
the trackpad apparatus based on changes in pressure data. For
example, the controller 230 may be configured to compare current
pressure data with previous pressure data to detect such movement.
In such approaches, filtered pressure data may be used to indicate
mouse clicks, or may be used to indicate other desired interactions
with a GUI, thus allowing a user to interact with objects in a GUI
(e.g., select objects, launch programs from icons and/or move
objects) without having to use separate buttons.
Referring to FIG. 2B, an example trackpad 250 is illustrated. The
trackpad 250 may be implemented, for example, in the computing
device 100 as the trackpad apparatus 130 and in the computing
device 150 as the keyboard and trackpad apparatus 170. Of course,
the trackpad 250 may be implemented in conjunction with other
computing devices and the computing devices 100 and 150 may include
pressure-sensitive trackpads having other configurations. The
trackpad 250 may function similar to the trackpad 200 of FIG. 2A
with a difference being that the trackpad 250 includes a capacitive
controller 260 and a resistive controller 270 in place of the
single controller 230 of FIG. 2A. The trackpad 250 also includes a
synchronizer 280 to synchronize the detection scans from both the
capacitive controller 260 and the resistive controller 270. The
capacitive controller 260 and the resistive controller 270 divide
the functionality of the controller 230 of FIG. 2A with the
capacitive controller 260 operatively coupled to the capacitive
sensor 210 and the resistive controller 270 operably coupled to the
resistive sensor 220. The capacitive controller 260 is configured
to work in conjunction with the capacitive sensor 210 in the same
manner controller 230 worked in conjunction with the capacitive
sensor 210, as described above with respect to FIG. 2A. Similarly,
the resistive controller 270 is configured to work in conjunction
with the resistive sensor 220 in the same manner controller 230
worked in conjunction with the resistive sensor 220, as described
above with respect to FIG. 2A.
The synchronizer 280 is configured to coordinate with the
capacitive controller 260 and the resistive controller 270 to run
detection scans simultaneously or nearly simultaneously such that
the scans both complete at substantially a same time in order to
run efficiently.
FIG. 3 is a diagram illustrating a pressure-sensitive trackpad
apparatus 300 in accordance with an example implementation. The
trackpad 300 shown in FIG. 3 illustrates an example structure that
may be used to implement a pressure-sensitive trackpad apparatus.
For instance, the structure of the trackpad 300 may be used to
implement the trackpad 200 shown in FIG. 2A and the trackpad 250
shown in FIG. 2B. Accordingly, for illustrative purposes, like
elements of the trackpad 300 are referenced with 300 series
reference numbers corresponding with the 200 series reference
number used in FIGS. 2A and 2B. Also, while not shown in FIG. 3,
the trackpad 300 may be coupled with a controller in like fashion
as shown for the controller 230 in the trackpad 200 illustrated in
FIG. 2A or the controllers 260 and 270 and synchronizer 280 in the
trackpad 250 illustrated in FIG. 2B.
As illustrated in FIG. 3, the trackpad 300 includes a capacitive
sensor 310, a resistive sensor 320, an optional insulating layer
330 that is disposed between the capacitive sensor 310 and the
resistive sensor 320, and a chassis ground 340. The upper surface
350 of the trackpad 300 may operate as a tactile sensing surface
for the trackpad 300 to gather touch data, such as in the manners
described herein.
In the trackpad 300, the capacitive sensor 310 and the resistive
sensor 320 may be implemented and operate in a similar fashion as
was discussed above with respect to the capacitive sensor 210 and
the resistive sensor 220 of the trackpads 200 and 250 shown in
FIGS. 2A and 2B. Accordingly, for purposes of brevity and clarity,
the entirety of the details of the capacitive sensor 210 and the
resistive sensor 220 are not repeated again here with respect to
the capacitive sensor 310 and the resistive sensor 320. The
capacitive sensor 310 may be a single layer sensor or a multi-layer
sensor.
As is indicated in FIG. 3, the resistive sensor 320 may be
implemented with two layers disposed on either side of a
compressible membrane. The particular arrangement of the resistive
matrix and the compressible membrane of the resistive sensor 320
will depend on the particular implementation. One such
implementation is illustrated in FIGS. 4A and 4B, as discussed
further below. Of course, other arrangements are possible.
In the trackpad 300, the stiffness (e.g., material) of each of the
capacitive sensor 310, the insulating layer 330, the resistive
layer(s) of the resistive sensor 320, and the compressible membrane
of the resistive sensor 320 may be selected such that the
compressible membrane is the first to displace when pressure is
applied to the surface 350, such as by a user's finger or fingers.
The chassis ground 340 may be implemented using a metal frame, such
as previously described. In such approaches, the chassis ground
would be highly resistant to being displaced as a result of
pressure applied to the surface 350 of the trackpad 300.
FIGS. 4A and 4B are diagrams illustrating operation of a
pressure-sensitive trackpad apparatus 400 in accordance with an
example implementation. The trackpad 400 shown in FIGS. 4A and 4B
illustrates another example structure of a pressure-sensitive
trackpad apparatus that may be used to implement the trackpads 200,
250 and 300 shown, respectively, in FIGS. 2A, 2B and 3.
Accordingly, for illustrative purposes, like elements of the
trackpad 400 are referenced with 400 series reference numbers
corresponding with the 200 and 300 series reference numbers used in
FIGS. 2A, 2B and 3. While not shown in FIGS. 4A and 4B, the
trackpad 400 may be coupled with a controller in like fashion as
shown for the controller 230 in the trackpad 200 illustrated in
FIG. 2A or multiple controllers 260 and 270 and synchronizer 280
illustrated in FIG. 2B.
As illustrated in FIGS. 4A and 4B, the trackpad 400 includes a
capacitive sensor 410, a resistive sensor 420, a PCB or a flexible
printed circuit substrate (FPC) substrate 430 that is disposed
between the capacitive sensor 410 and the resistive sensor 420, and
a chassis ground 440. In the trackpad 400, the resistive sensor 420
includes a resistive sensor top layer 420a, a compressible membrane
420b that is disposed below the resistive sensor top layer 420a and
a resistive sensor bottom layer 420c.
The compressible membrane 420b may be implemented using, for
example, silicone, synthetic polymers, such as polyethylene
terephthalate (PET), air, or a combination these or other
materials. For instance, in an example implementation of the
trackpad 400, the compressible membrane 420b may include a matrix
of PET spacer dots, which creates a gap between the resistive
sensor top 420a and the resistive sensor bottom 420c, while the
rest of the compressible membrane 420b is air. The PCB substrate
430 may be implemented using a glass-reinforced epoxy laminate PCB
substrate, such as FR-4, for example. The specific materials used
will, of course, depend on the particular implementation.
As was discussed with respect to the trackpad 300, the stiffness
(materials) of each of the capacitive sensor 410; the PCB substrate
430; the resistive sensor layers 420a and 420c; and the
compressible membrane 420b may be selected such that the
compressible membrane 420b is the first to displace when pressure
is applied to the top surface of the trackpad 400, such as by a
user's finger or fingers. Further, the chassis ground 440 may be
implemented in like fashion as was discussed above with respect to
the chassis ground 340, e.g., so as to be resistant to
displacement.
In the trackpad 400, the capacitive sensor 410 and the resistive
sensor 420 may be implemented and operate in a similar fashion as
was discussed above with respect to the capacitive sensor 210 and
the resistive sensor 220 of the trackpads 200 and 250 shown in
FIGS. 2A and 2B. Accordingly, for purposes of brevity and clarity,
the entirety of the details of the capacitive sensor 210 and the
resistive sensor 220 are not repeated again here with respect to
the capacitive sensor 410 and the resistive sensor 420.
In FIGS. 4A and 4B, a user's fingers 450 and 460 are illustrated as
being in contact (e.g., electrical contact) with a top surface of
the trackpad 400. The fingers 450 and 460 are also shown as being
connected to an electrical ground 470, where the user would provide
an electrical ground with respect to the top surface of the
trackpad 400.
In like fashion as previously described, the user's fingers 450 and
460 may shunt charge away from the capacitive sensor 410 to the
electrical ground 470, thereby changing the apparent capacitance of
the capacitive sensor 410 where it is contacted by the user's
fingers 450 and 460. A controller, such as the controller 230 (or
controller 260 of FIG. 2B), (not shown in FIGS. 4A and 4B) coupled
with the trackpad 400 may detect such changes in apparent
capacitance (as touch data) by detecting corresponding reductions
in charge coupling in the capacitive sensor 410 where it is
contacted by the user's fingers 450 and 460. Additionally, movement
of the user's fingers 450 and 460 across the surface of the
trackpad apparatus 400 may be detected using the techniques
described here, such as those that were discussed above with
respect to FIGS. 2A and 2B.
As shown in FIG. 4A, the user's fingers 450 and 460 are not
applying pressure to the surface of the trackpad 400. In this
situation, voltage in the resistive sensor 420 would be
substantially uniform across its resistive matrix.
The compressible membrane 420b is disposed between the resistive
layers 420a and 420b of the resistive sensor 420 of the trackpad
400. Therefore, in this embodiment, the compressible membrane 420b
is part of the resistive sensor 420.
As shown in FIG. 4A, the fingers 450 and 460 are not applying
pressure to the surface of the trackpad 400. In this situation,
voltage across the resistive sensor 420 would be substantially
uniform across its voltage matrix.
As shown in FIG. 4B, pressure is being applied to the surface of
the trackpad 400 by the fingers 450 and 460, with more pressure
being applied by the finger 450 than by the finger 460. As
illustrated, the pressure by the fingers 450 and 460 results in
corresponding displacements of the compressible membrane 420b, the
resistive layer 420a, the PCB substrate 430 and the capacitive
sensor 410. As discussed above, the stiffness of each of these
layers may be selected such that the compressible membrane 420b is
the first displace when pressure is applied to the surface of the
trackpad 400.
In this situation, the displacements of the resistive layer 420a
and the compressible membrane 420b under the fingers 450 and 460
will cause contact with the resistive layer 420c. The contact of
the resistive layers 420a and 420c will cause respective
location-specific increases in voltage (i.e., a voltage conduction)
of the resistive sensor 420 where the displacements occur. A
controller, such as the controller 230 shown in FIG. 2A (or
controller 270 of FIG. 2B), coupled with the trackpad 400 may
detect such increases in voltage as pressure data. Movement of the
fingers 450 and 460 across the surface of the trackpad 400 while
applying pressure may be detected from such pressure data using the
techniques described herein. Also, pressure data and touch data for
the trackpad apparatus 400 may be filtered using the techniques
described herein, such as discussed with reference to FIG. 2A, FIG.
2B and FIG. 5, for example.
A controller coupled with the trackpad 400 may also be configured
to determine the respective amount of pressure applied by each of
the fingers 450 and 460 to the surface of the trackpad 400. For
example, because the finger 450 is applying more pressure than the
finger 460 and causes a larger displacement, the location-specific
increase in voltage in the resistive sensor 420 associated with the
displacement from the finger 450 will be greater than the voltage
conduction in the resistive sensor 420 associated with the
displacement from the finger 460.
The trackpad apparatus 400, using a controller, may be configured
to determine an amount of pressure applied by each of the fingers
450 and 460, from corresponding pressure data. For instance, the
pressure amounts may be determined based on respective amounts of
location-specific increases in voltage in the resistive sensor 420.
Such determinations may be provided to a computing system, such as
the computing system 100 or 150, by the trackpad 400 (e.g., using a
controller) and may affect different actions in a GUI based on the
amount of pressure applied. For example, a first amount of pressure
may cause an item to be selected in a GUI and a second amount of
pressure (e.g., greater than the first amount) may cause the item
to be opened, such as using a default program or by running a
program associated with an icon, as some examples. The amount of
pressure also may be used to distinguish between selection of keys
in a keyboard versus tracking gestures to control a cursor such as
with combined keyboard and trackpad 170 of FIG. 1B. For example,
when an amount of pressure as detected by the resistive sensor
meets or exceeds a particular threshold pressure, then a keyboard
action may be registered instead of a tracking gesture. Of course,
such indications of an amount of pressure applied may be used in a
number of other ways depending on the particular implementation
and/or situation.
FIG. 5 is a diagram illustrating pattern matching and rejection
(pattern filtering) criteria 500 in accordance with an example
implementation. In an example implementation, the pattern filtering
criteria 500 may be used to implement the pattern filtering
criteria 240 shown in FIGS. 2A and 2B. For instance, the pattern
filtering criteria 500 may be used to filter touch data and/or
pressure data for a trackpad apparatus using the techniques that
have been described herein, such as with respect to FIGS. 2A and
2B. As indicated in FIG. 5, the pattern filtering criteria 500 may
define acceptable patterns, such as finger ellipses which would not
be filtered out of touch data and/or pressure data received by a
trackpad apparatus. The pattern filtering criteria 500 may also
define unacceptable patterns, such as palm or side of hand
patterns, which would be filtered out of touch data and/or pressure
data received by a trackpad apparatus.
As shown in FIG. 5, the pattern filtering criteria 500 includes
dimensional criteria 510, graphical criteria 520 and area criteria
530. In such an approach, the dimensional criteria 510 may define
dimensions for touch data and/or pressure data that should be
accepted, or may define dimensions for touch data and/or pressure
data that should be rejected. In some implementations, the
dimensional criteria 510 may define both pattern dimensions that
should be accepted and pattern dimensions that should be rejected.
The graphical criteria 520 may define geometric patterns in a
graphical form, which may include graphical patterns that should be
accepted and/or graphical patterns that should be rejected. The
area criteria 530 may define patterns that should be accepted
and/or patterns that should be rejected based on a respective area
of a given pattern. For instance, in one implementation, an area
threshold may be defined in the area criteria 530. In such an
approach, touch data patterns and/or pressure data patterns with an
area less than the area threshold may be accepted and patterns with
an area greater than the area threshold may be rejected. Of course,
other approaches for defining pattern filtering criteria are
possible.
FIG. 6 is an example flow diagram illustrating example operations
of the trackpad apparatus of FIGS. 2A, 2B, 3, 4A and 4B as
implemented in example computing devices of FIGS. 1A and 1B. FIG. 6
includes a process 600. The process 600 includes detecting one or
more objects on a top surface of a trackpad device using at least
one controller and a capacitive sensor (610). For example, the
capacitive sensor 210 and the controller 230 may be used to detect
one or more objects on a top surface of trackpad 200.
Process 600 includes detecting one or more objects on the top
surface using the at least one controller and a resistive sensor
independent of the detection by the at least one controller and the
capacitive sensor (620). For example, independent of detecting
objects using the capacitive sensor 210 and controller 203, the
resistive sensor 220 and controller 230 may be used to detect one
or more objects on the top surface of the trackpad 200.
Process 600 includes determining locations of the one or more
objects on the top surface using information from the detection by
the at least one controller and capacitive sensor and information
from the detection by the at least one controller and the resistive
sensor (630). For example, the controller 230 may be configured to
determine the locations of the one or more objects on the top
surface of the trackpad 200 using detection information from both
the capacitive sensor 210 and the resistive sensor 220. The
detection information from both the capacitive sensor 210 and the
resistive sensor 220 also may be used to distinguish between
different types of gestures or keyboard actions. For example, the
information may be used to distinguish between keyboard actions and
tracking gestures (e.g., on a combined keyboard and trackpad such
as keyboard and trackpad 170 of FIG. 1B.
While certain features of the described implementations have been
illustrated as described herein, many modifications, substitutions,
changes and equivalents will now occur to those skilled in the art.
It is, therefore, to be understood that the appended claims are
intended to cover all such modifications and changes as fall within
the scope of the implementations. It should be understood that they
have been presented by way of example only, not limitation, and
various changes in form and details may be made. Any portion of the
apparatus and/or methods described herein may be combined in any
combination, except mutually exclusive combinations. The
implementations described herein can include various combinations
and/or sub-combinations of the functions, components and/or
features of the different implementations described.
* * * * *